Hi I am using ginac in a symbolic regression program. It generates different polynomials using genetic programming, mulitplies each monomial by a weight and then fits the resulting expression using regression. I need to extract each monomial from the polynomial. Until now , I have been getting by only dealing with the case where the top level class is "add", and the program worked well enough for me to publish a paper on the use of symbolic regression in software modelling. Yes , I wanted to let the authors know, they have another citation :-). But this restricts the program. Is there a better way to do this ? Will ex::expand () convert the expression to a polynomial I should mention that the ginac expression itself is generated from a genetic evolved tree, so that I can generate all the monomials while doing this conversion, but that will leave me with the task of collecting like terms, something I would rather have done for me :-). Thanks Anish -- Anish Muttreja ~ Graduate Student Electrical Engineering ~ Princeton University ======================================================== As an adolescent I aspired to lasting fame, I craved factual certainty, and I thirsted for a meaningful vision of human life - so I became a scientist. This is like becoming an archbishop so you can meet girls. -Matt Cartmill, anthropology professor and author (1943- )